Legacy-compatible control frames

ABSTRACT

Certain aspects of the present disclosure provide techniques and apparatus for using different MAC addresses in frames for the same station to indicate how to process the frames. In this manner, frames for IEEE 802.11ac can carry information not present in legacy frames (e.g., frames according to IEEE 802.11a/n), but these frames may be interpreted by legacy devices in a legacy way. One example method generally includes receiving a first frame comprising an indication of a first MAC address and processing the received first frame based on the first MAC address. For certain aspects, the method further includes receiving a second frame comprising an indication of a second MAC address, wherein the second MAC address is different than the first address; and processing the received second frame based on the second MAC address, such that the processing of the second frame is different than the processing of the first frame.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. Utility application Ser. No.13/245,555, (Atty. Docket No. 102985), filed Sep. 26, 2011, which claimsbenefit of U.S. Provisional Patent Application Ser. No. 61/388,896(Atty. Docket No. 102985P1), filed Oct. 1, 2010, which is hereinincorporated by reference in its entirety.

BACKGROUND

1. Field

Certain aspects of the present disclosure generally relate to wirelesscommunications and, more particularly, to using different Media AccessControl (MAC) addresses in frames for the same apparatus (e.g., a userterminal) to indicate how to process the frames.

2. Background

In order to address the issue of increasing bandwidth requirementsdemanded for wireless communications systems, different schemes arebeing developed to allow multiple user terminals to communicate with asingle access point by sharing the channel resources while achievinghigh data throughputs. Multiple Input Multiple Output (MIMO) technologyrepresents one such approach that has recently emerged as a populartechnique for next generation communication systems. MIMO technology hasbeen adopted in several emerging wireless communications standards suchas the Institute of Electrical and Electronics Engineers (IEEE) 802.11standard. The IEEE 802.11 denotes a set of Wireless Local Area Network(WLAN) air interface standards developed by the IEEE 802.11 committeefor short-range communications (e.g., tens of meters to a few hundredmeters).

A MIMO system employs multiple (N_(T)) transmit antennas and multiple(N_(R)) receive antennas for data transmission. A MIMO channel formed bythe N_(T) transmit and N_(R) receive antennas may be decomposed intoN_(S) independent channels, which are also referred to as spatialchannels, where N_(S)≦min{N_(T), N_(R)}. Each of the N_(S) independentchannels corresponds to a dimension. The MIMO system can provideimproved performance (e.g., higher throughput and/or greaterreliability) if the additional dimensionalities created by the multipletransmit and receive antennas are utilized.

In wireless networks with a single Access Point (AP) and multiple userstations (STAs), concurrent transmissions may occur on multiple channelstoward different stations, both in the uplink and downlink direction.Many challenges are present in such systems.

SUMMARY

Certain aspects of the present disclosure generally relate to usingdifferent Media Access Control (MAC) addresses in frames for the sameapparatus (e.g., a user terminal) to indicate how to process (e.g.,interpret and parse) the frames. In this manner, frames for IEEE802.11ac can carry information not present in legacy frames (e.g.,frames in accordance with amendments to the IEEE 802.11 standard priorto 802.11ac, such as IEEE 802.11a or 802.11n), but these frames may beinterpreted by legacy devices in a legacy way.

Certain aspects of the present disclosure provide a method for wirelesscommunications. The method generally includes receiving, at anapparatus, a first frame comprising an indication of a first MAC addressand parsing the received first frame based on the first MAC address.

Certain aspects of the present disclosure provide an apparatus forwireless communications. The apparatus generally includes a receiverconfigured to receive a first frame comprising an indication of a firstMAC address and a processing system configured to parse the receivedfirst frame based on the first MAC address.

Certain aspects of the present disclosure provide an apparatus forwireless communications. The apparatus generally includes means forreceiving a first frame comprising an indication of a first MAC addressand means for parsing the received first frame based on the first MACaddress.

Certain aspects of the present disclosure provide a computer-programproduct for wireless communications. The computer-program productgenerally includes a computer-readable medium having instructionsexecutable to receive, at an apparatus, a frame comprising an indicationof a MAC address and to parse the received frame based on the MACaddress.

Certain aspects of the present disclosure provide a wireless node. Thewireless node generally includes at least one antenna; a receiverconfigured to receive, via the at least one antenna, a frame comprisingan indication of a MAC address; and a processing system configured toparse the received frame based on the MAC address.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentdisclosure can be understood in detail, a more particular description,briefly summarized above, may be had by reference to aspects, some ofwhich are illustrated in the appended drawings. It is to be noted,however, that the appended drawings illustrate only certain typicalaspects of this disclosure and are therefore not to be consideredlimiting of its scope, for the description may admit to other equallyeffective aspects.

FIG. 1 illustrates a diagram of a wireless communications network inaccordance with certain aspects of the present disclosure.

FIG. 2 illustrates a block diagram of an example access point and userterminals in accordance with certain aspects of the present disclosure.

FIG. 3 illustrates a block diagram of an example wireless device inaccordance with certain aspects of the present disclosure.

FIG. 4 illustrates an example frame structure for wirelesscommunications in accordance with certain aspects of the presentdisclosure.

FIGS. 5A-5C illustrate example frame formats, for control and managementframes, for the Media Access Control (MAC) header in the frame structureof FIG. 4, in accordance with certain aspects of the present disclosure.

FIG. 6A illustrates an example MAC address structure, in accordance withcertain aspects of the present disclosure.

FIG. 6B illustrates an example MAC address in canonical form with theleast significant bit (LSB) in each byte transmitted first, inaccordance with certain aspects of the present disclosure.

FIG. 7 illustrates example operations to process, from the perspectiveof a receiving entity, a received frame based on the MAC address of theframe, in accordance with certain aspects of the present disclosure.

FIG. 7A illustrates example means for performing the operations shown inFIG. 7.

FIGS. 8-11 illustrate example frame exchanges between two wirelessdevices using legacy-compatible control frames, in accordance withcertain aspects of the present disclosure.

DETAILED DESCRIPTION

Various aspects of the disclosure are described more fully hereinafterwith reference to the accompanying drawings. This disclosure may,however, be embodied in many different forms and should not be construedas limited to any specific structure or function presented throughoutthis disclosure. Rather, these aspects are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the disclosure to those skilled in the art. Based on theteachings herein one skilled in the art should appreciate that the scopeof the disclosure is intended to cover any aspect of the disclosuredisclosed herein, whether implemented independently of or combined withany other aspect of the disclosure. For example, an apparatus may beimplemented or a method may be practiced using any number of the aspectsset forth herein. In addition, the scope of the disclosure is intendedto cover such an apparatus or method which is practiced using otherstructure, functionality, or structure and functionality in addition toor other than the various aspects of the disclosure set forth herein. Itshould be understood that any aspect of the disclosure disclosed hereinmay be embodied by one or more elements of a claim.

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any aspect described herein as “exemplary”is not necessarily to be construed as preferred or advantageous overother aspects.

Although particular aspects are described herein, many variations andpermutations of these aspects fall within the scope of the disclosure.Although some benefits and advantages of the preferred aspects arementioned, the scope of the disclosure is not intended to be limited toparticular benefits, uses, or objectives. Rather, aspects of thedisclosure are intended to be broadly applicable to different wirelesstechnologies, system configurations, networks, and transmissionprotocols, some of which are illustrated by way of example in thefigures and in the following description of the preferred aspects. Thedetailed description and drawings are merely illustrative of thedisclosure rather than limiting, the scope of the disclosure beingdefined by the appended claims and equivalents thereof.

An Example Wireless communications System

The techniques described herein may be used for various broadbandwireless communication systems, including communication systems that arebased on an orthogonal multiplexing scheme. Examples of suchcommunication systems include Spatial Division Multiple Access (SDMA),Time Division Multiple Access (TDMA), Orthogonal Frequency DivisionMultiple Access (OFDMA) systems, Single-Carrier Frequency DivisionMultiple Access (SC-FDMA) systems, and so forth. An SDMA system mayutilize sufficiently different directions to simultaneously transmitdata belonging to multiple user terminals. A TDMA system may allowmultiple user terminals to share the same frequency channel by dividingthe transmission signal into different time slots, each time slot beingassigned to different user terminal. An OFDMA system utilizes orthogonalfrequency division multiplexing (OFDM), which is a modulation techniquethat partitions the overall system bandwidth into multiple orthogonalsub-carriers. These sub-carriers may also be called tones, bins, etc.With OFDM, each sub-carrier may be independently modulated with data. AnSC-FDMA system may utilize interleaved FDMA (IFDMA) to transmit onsub-carriers that are distributed across the system bandwidth, localizedFDMA (LFDMA) to transmit on a block of adjacent sub-carriers, orenhanced FDMA (EFDMA) to transmit on multiple blocks of adjacentsub-carriers. In general, modulation symbols are sent in the frequencydomain with OFDM and in the time domain with SC-FDMA.

The teachings herein may be incorporated into (e.g., implemented withinor performed by) a variety of wired or wireless apparatuses (e.g.,nodes). In some aspects, a wireless node implemented in accordance withthe teachings herein may comprise an access point or an access terminal.

An access point (“AP”) may comprise, be implemented as, or known as aNode B, Radio Network Controller (“RNC”), evolved Node B (eNB), BaseStation Controller (“BSC”), Base Transceiver Station (“BTS”), BaseStation (“BS”), Transceiver Function (“TF”), Radio Router, RadioTransceiver, Basic Service Set (“BSS”), Extended Service Set (“ESS”),Radio Base Station (“RBS”), or some other terminology.

An access terminal (“AT”) may comprise, be implemented as, or known as astation (STA), a subscriber station, a subscriber unit, a mobile station(MS), a remote station, a remote terminal, a user terminal (UT), a useragent, a user device, user equipment (UE), a user station, or some otherterminology. In some implementations, an access terminal may comprise acellular telephone, a cordless telephone, a Session Initiation Protocol(“SIP”) phone, a wireless local loop (“WLL”) station, a personal digitalassistant (“PDA”), a handheld device having wireless connectioncapability, a tablet, or some other suitable processing device connectedto a wireless modem. Accordingly, one or more aspects taught herein maybe incorporated into a phone (e.g., a cellular phone or smart phone), acomputer (e.g., a laptop), a portable communication device, a portablecomputing device (e.g., a personal data assistant), an entertainmentdevice (e.g., a music or video device, or a satellite radio), a globalpositioning system (GPS) device, or any other suitable device that isconfigured to communicate via a wireless or wired medium. In someaspects, the node is a wireless node. Such wireless node may provide,for example, connectivity for or to a network (e.g., a wide area networksuch as the Internet or a cellular network) via a wired or wirelesscommunication link.

FIG. 1 illustrates a multiple-access multiple-input multiple-output(MIMO) system 100 with access points and user terminals. For simplicity,only one access point 110 is shown in FIG. 1. An access point isgenerally a fixed station that communicates with the user terminals andmay also be referred to as a base station or some other terminology. Auser terminal may be fixed or mobile and may also be referred to as amobile station, a wireless device, or some other terminology. Accesspoint 110 may communicate with one or more user terminals 120 at anygiven moment on the downlink and uplink. The downlink (i.e., forwardlink) is the communication link from the access point to the userterminals, and the uplink (i.e., reverse link) is the communication linkfrom the user terminals to the access point. A user terminal may alsocommunicate peer-to-peer with another user terminal. A system controller130 couples to and provides coordination and control for the accesspoints.

While portions of the following disclosure will describe user terminals120 capable of communicating via Spatial Division Multiple Access(SDMA), for certain aspects, the user terminals 120 may also includesome user terminals that do not support SDMA. Thus, for such aspects, anAP 110 may be configured to communicate with both SDMA and non-SDMA userterminals. This approach may conveniently allow older versions of userterminals (“legacy” stations) to remain deployed in an enterprise,extending their useful lifetime, while allowing newer SDMA userterminals to be introduced as deemed appropriate.

The system 100 employs multiple transmit and multiple receive antennasfor data transmission on the downlink and uplink. The access point 110is equipped with N_(ap) antennas and represents the multiple-input (MI)for downlink transmissions and the multiple-output (MO) for uplinktransmissions. A set of K selected user terminals 120 collectivelyrepresents the multiple-output for downlink transmissions and themultiple-input for uplink transmissions. For pure SDMA, it is desired tohave N_(ap)≧K≧1 if the data symbol streams for the K user terminals arenot multiplexed in code, frequency or time by some means. K may begreater than N_(ap) if the data symbol streams can be multiplexed usingTDMA technique, different code channels with CDMA, disjoint sets ofsubbands with OFDM, and so on. Each selected user terminal transmitsuser-specific data to and/or receives user-specific data from the accesspoint. In general, each selected user terminal may be equipped with oneor multiple antennas (i.e., N_(ut)≧1). The K selected user terminals canhave the same or different number of antennas.

The SDMA system may be a time division duplex (TDD) system or afrequency division duplex (FDD) system. For a TDD system, the downlinkand uplink share the same frequency band. For an FDD system, thedownlink and uplink use different frequency bands. MIMO system 100 mayalso utilize a single carrier or multiple carriers for transmission.Each user terminal may be equipped with a single antenna (e.g., in orderto keep costs down) or multiple antennas (e.g., where the additionalcost can be supported). The system 100 may also be a TDMA system if theuser terminals 120 share the same frequency channel by dividingtransmission/reception into different time slots, each time slot beingassigned to a different user terminal 120.

FIG. 2 illustrates a block diagram of access point 110 and two userterminals 120 m and 120 x in MIMO system 100. The access point 110 isequipped with N_(t) antennas 224 a through 224 t. User terminal 120 m isequipped with N_(ut,m) antennas 252 ma through 252 mu, and user terminal120 x is equipped with N_(ut,x) antennas 252 xa through 252 xu. Theaccess point 110 is a transmitting entity for the downlink and areceiving entity for the uplink. Each user terminal 120 is atransmitting entity for the uplink and a receiving entity for thedownlink. As used herein, a “transmitting entity” is an independentlyoperated apparatus or device capable of transmitting data via a wirelesschannel, and a “receiving entity” is an independently operated apparatusor device capable of receiving data via a wireless channel. In thefollowing description, the subscript “dn” denotes the downlink, thesubscript “up” denotes the uplink, N_(up) user terminals are selectedfor simultaneous transmission on the uplink, N_(dn) user terminals areselected for simultaneous transmission on the downlink, N_(up) may ormay not be equal to N_(dn), and N_(up) and N_(dn) may be static valuesor can change for each scheduling interval. The beam-steering or someother spatial processing technique may be used at the access point anduser terminal.

On the uplink, at each user terminal 120 selected for uplinktransmission, a TX data processor 288 receives traffic data from a datasource 286 and control data from a controller 280. TX data processor 288processes (e.g., encodes, interleaves, and modulates) the traffic datafor the user terminal based on the coding and modulation schemesassociated with the rate selected for the user terminal and provides adata symbol stream. A TX spatial processor 290 performs spatialprocessing on the data symbol stream and provides N_(ut,m) transmitsymbol streams for the N_(ut,m) antennas. Each transmitter unit (TMTR)254 receives and processes (e.g., converts to analog, amplifies,filters, and frequency upconverts) a respective transmit symbol streamto generate an uplink signal. N_(ut,m) transmitter units 254 provideN_(ut,m) uplink signals for transmission from N_(ut,m) antennas 252 tothe access point.

N_(up) user terminals may be scheduled for simultaneous transmission onthe uplink. Each of these user terminals performs spatial processing onits data symbol stream and transmits its set of transmit symbol streamson the uplink to the access point.

At access point 110, N_(ap) antennas 224 a through 224 ap receive theuplink signals from all N_(up) user terminals transmitting on theuplink. Each antenna 224 provides a received signal to a respectivereceiver unit (RCVR) 222. Each receiver unit 222 performs processingcomplementary to that performed by transmitter unit 254 and provides areceived symbol stream. An RX spatial processor 240 performs receiverspatial processing on the N_(ap) received symbol streams from N_(ap)receiver units 222 and provides N_(up) recovered uplink data symbolstreams. The receiver spatial processing is performed in accordance withthe channel correlation matrix inversion (CCMI), minimum mean squareerror (MMSE), soft interference cancellation (SIC), or some othertechnique. Each recovered uplink data symbol stream is an estimate of adata symbol stream transmitted by a respective user terminal. An RX dataprocessor 242 processes (e.g., demodulates, deinterleaves, and decodes)each recovered uplink data symbol stream in accordance with the rateused for that stream to obtain decoded data. The decoded data for eachuser terminal may be provided to a data sink 244 for storage and/or acontroller 230 for further processing.

On the downlink, at access point 110, a TX data processor 210 receivestraffic data from a data source 208 for N_(dn) user terminals scheduledfor downlink transmission, control data from a controller 230, andpossibly other data from a scheduler 234. The various types of data maybe sent on different transport channels. TX data processor 210 processes(e.g., encodes, interleaves, and modulates) the traffic data for eachuser terminal based on the rate selected for that user terminal. TX dataprocessor 210 provides N_(dn) downlink data symbol streams for theN_(dn) user terminals. A TX spatial processor 220 performs spatialprocessing (such as a precoding or beamforming, as described in thepresent disclosure) on the N_(dn) downlink data symbol streams, andprovides N_(ap) transmit symbol streams for the N_(ap) antennas. Eachtransmitter unit 222 receives and processes a respective transmit symbolstream to generate a downlink signal. N_(ap) transmitter units 222providing N_(ap) downlink signals for transmission from N_(ap) antennas224 to the user terminals.

At each user terminal 120, N_(ut,m) antennas 252 receive the N_(ap)downlink signals from access point 110. Each receiver unit 254 processesa received signal from an associated antenna 252 and provides a receivedsymbol stream. An RX spatial processor 260 performs receiver spatialprocessing on N_(ut,m) received symbol streams from N_(ut,m) receiverunits 254 and provides a recovered downlink data symbol stream for theuser terminal. The receiver spatial processing is performed inaccordance with the CCMI, MMSE or some other technique. An RX dataprocessor 270 processes (e.g., demodulates, deinterleaves and decodes)the recovered downlink data symbol stream to obtain decoded data for theuser terminal.

At each user terminal 120, a channel estimator 278 estimates thedownlink channel response and provides downlink channel estimates, whichmay include channel gain estimates, SNR estimates, noise variance and soon. Similarly, a channel estimator 228 estimates the uplink channelresponse and provides uplink channel estimates. Controller 280 for eachuser terminal typically derives the spatial filter matrix for the userterminal based on the downlink channel response matrix H_(dn,m) for thatuser terminal. Controller 230 derives the spatial filter matrix for theaccess point based on the effective uplink channel response matrixH_(up,eff). Controller 280 for each user terminal may send feedbackinformation (e.g., the downlink and/or uplink eigenvectors, eigenvalues,SNR estimates, and so on) to the access point. Controllers 230 and 280also control the operation of various processing units at access point110 and user terminal 120, respectively.

FIG. 3 illustrates various components that may be utilized in a wirelessdevice 302 that may be employed within the MIMO system 100. The wirelessdevice 302 is an example of a device that may be configured to implementthe various methods described herein. The wireless device 302 may be anaccess point 110 or a user terminal 120.

The wireless device 302 may include a processor 304 which controlsoperation of the wireless device 302. The processor 304 may also bereferred to as a central processing unit (CPU). Memory 306, which mayinclude both read-only memory (ROM) and random access memory (RAM),provides instructions and data to the processor 304. A portion of thememory 306 may also include non-volatile random access memory (NVRAM).The processor 304 typically performs logical and arithmetic operationsbased on program instructions stored within the memory 306. Theinstructions in the memory 306 may be executable to implement themethods described herein.

The wireless device 302 may also include a housing 308 that may includea transmitter 310 and a receiver 312 to allow transmission and receptionof data between the wireless device 302 and a remote location. Thetransmitter 310 and receiver 312 may be combined into a transceiver 314.A single or a plurality of transmit antennas 316 may be attached to thehousing 308 and electrically coupled to the transceiver 314. Thewireless device 302 may also include (not shown) multiple transmitters,multiple receivers, and multiple transceivers.

The wireless device 302 may also include a signal detector 318 that maybe used in an effort to detect and quantify the level of signalsreceived by the transceiver 314. The signal detector 318 may detect suchsignals as total energy, energy per subcarrier per symbol, powerspectral density and other signals. The wireless device 302 may alsoinclude a digital signal processor (DSP) 320 for use in processingsignals.

The various components of the wireless device 302 may be coupledtogether by a bus system 322, which may include a power bus, a controlsignal bus, and a status signal bus in addition to a data bus.

Example Frame Structures

In order to communicate, the access point (AP) 110 and the userterminals 120 in a wireless network (e.g., system 100 illustrated inFIG. 1) may exchange messages according to certain frame structures.FIG. 4 illustrates an example frame structure 400 for wirelesscommunications in accordance with certain aspects of the presentdisclosure. The frame structure 400 may comprise a preamble 401, a MediaAccess Control (MAC) header 402, a frame body 404, and a frame checksequence (FCS) 406. The frame structure 400 may be used for controlframes, data frames, and management frames according to the IEEE 802.11standard, although control frames may not include a frame body.

FIG. 4 also illustrates a general frame format 408 for the MAC header402. The general frame format 408, which is also the same as the dataframe format, may comprise 30 octets broken down as follows: two octetsfor a frame control (FC) field 410, two octets for a Duration/ID field412, six octets for an Address1 field 414, six octets for an Address2field 416, six octets for an Address3 field 418, two octets for aSequence Control field 420, and six octets for an Address4 field 422.The four address fields 414, 416, 418, 422 may comprise a Source Address(SA), a Destination Address (DA), or additional addresses—such as aTransmitter Address (TA), a Receiver Address (RA), or a Basic ServiceSet Identifier (BSSID)—used to filter multicast frames to allowtransparent mobility in IEEE 802.11. These addresses may be MACaddresses of various network devices, such as a user terminal 120 or anaccess point 110.

FIG. 5A illustrates an example frame format 500 for a short controlframe, such as a Request to Send (RTS) frame. This control frame format500 may include the FC field 410, the Duration field 412, an RA field502, and a TA field 504. As defined herein, the RA generally refers tothe MAC address to which the frame is sent over the wireless medium. TheRA may be an individual or a group address. The TA, as defined herein,generally refers to the MAC address of the station that transmitted theframe to the wireless medium.

FIG. 5B illustrates another example frame format 510 for a short controlframe, such as a Clear to Send (CTS) frame or an acknowledgment (ACK)frame. This control frame format 510 is similar to the control frameformat 500 in FIG. 5A, but without the TA field 504.

FIG. 5C illustrates a management frame format 520. In addition to the FCfield 410 and the Duration field 412, the management frame format 520may include a DA field 522, an SA field 524, a BSSID field 526, and aSequence Control field 420.

FIG. 6A illustrates an example MAC address structure 600. The MACaddress may comprise 6 octets (48 bits), where the first three octetsmay identify the organization that issued the MAC address and are knownas the Organizationally Unique Identifier (OUI) 602. The second threeoctets 604 are Network Interface Controller (NIC)-specific and may beassigned by the issuing organization in nearly any manner, subject tothe constraint of uniqueness.

In the MAC address structure 600, the least significant bit (LSB) of themost significant octet may be considered as the Individual/Group (I/G)address bit 606. The next LSB of this octet may be considered as theUniversally/Locally Administered address bit 608.

FIG. 6B illustrates an example MAC address AC-DE-48-00-00-80 (inhexadecimal) in canonical form with the LSB in each byte transmittedfirst. With this transmission order, the I/G address bit 606 and the U/LAdministered address bit are the first and second bits, respectively,transmitted in a wireless medium.

Example Legacy-Compatible Frames

IEEE 802.11ac is an amendment to the IEEE 802.11 standard that enableshigher throughput in 802.11 networks. The higher throughput is realizedthrough several measures, such as the use of MU-MIMO (multiuser multipleinput multiple output) and 80 MHz or 160 MHz channel bandwidth. IEEE802.11ac is also referred to as Very High Throughput (VHT).

New VHT-capable devices may employ control frames with additional ordifferent VHT-specific information. However, legacy devices (i.e.,devices supporting earlier amendments to the IEEE 802.11 standard, suchas 802.11a and 802.11n) may not be able to interpret certain VHT controlframes.

Accordingly what is needed are techniques and apparatus for definingcontrol frames for IEEE 802.11ac which can carry information that is notpresent in legacy control frames, yet the VHT control frames may beinterpreted by legacy devices in a legacy manner.

FIG. 7 illustrates example operations 700 to process, from theperspective of a receiving entity (e.g., a user terminal 120 or accesspoint 110), a received frame based on the MAC address of the frame. Theoperations 700 may begin, at 702, by receiving a first frame comprisingan indication of a first MAC address. At 704, the receiving entity mayprocess (e.g., interpret and/or parse) the received frame based on thefirst MAC address.

Processing the received first frame may involve interpreting the firstframe as a legacy frame or as a Very High Throughput (VHT) frame,according to the first MAC address. As used herein, “a legacy frame”generally refers to a frame in accordance with an amendment of the IEEE802.11 standard prior to the 802.11ac amendment, whereas “a VHT frame”generally refers to a frame in accordance with the 802.11ac amendment(or subsequent amendments) to the IEEE 802.11 standard.

For certain aspects, the receiving entity may receive a second framecomprising an indication of a second MAC address at 706, wherein thesecond MAC address is different than the first MAC address. At 708, thereceiving entity may process the received second frame based on thesecond MAC address, such that the processing of the second frame isdifferent than the processing of the first frame. For certain aspects,the receiving entity may receive a management frame signaling the firstMAC address (i.e., notifying the receiving entity that frames comprisingthe indication of the first MAC address are intended for the receivingentity), such that the receiving entity will know to process framesreceived with the first MAC address differently than frames receivedwith the second MAC address.

Certain aspects of the present disclosure involve transmitting new802.11ac-specific control frames to a second MAC address that isassociated with the same device. Frames that are received with the firstMAC address of the device may be processed as a typical legacy framewould be, such as according to the 802.11a amendment or the 802.11namendment to the IEEE 802.11 standard. Frames that are received with thesecond MAC address, however, may be processed according to differentrules as defined in 802.11ac (or later amendments to the IEEE 802.11standard).

The second MAC address may be transmitted in the RA field 502 of acontrol frame, such as a Request to Send (RTS) frame, a Clear to Send(CTS) frame, or an acknowledgment (ACK) frame. The second MAC addressmay also be transmitted in the DA field 522 of a management frame or inone of the address fields (e.g., the Address1 field 414 or the Address3field 418) of a data frame.

For certain aspects, the second MAC address may be a second uniqueglobal MAC address that is associated with the device.

For other aspects, the first and second MAC addresses may be nearly thesame, differing by only one or two bits, for example. For example, thesecond MAC address may be formed by setting the Individual/Group (I/G)address bit 606 of the first MAC address to 1, so that the second MACaddress is the group address version of the first MAC address. In otherwords, the I/G address bit 606 of the first MAC address is a 0. In thismanner, the first MAC address differs from the second MAC address byonly one address bit. As another example, the second MAC address may beformed by setting the Universally/Locally (U/L) Administered address bit608 of the first MAC address to 1, so that the second MAC address is thelocally administered version of the first MAC address. For certainaspects, these two ideas may be combined. For example, the second MACaddress may be formed by setting the I/G address bit 606 of the firstMAC address to 1 and setting the U/L Administered address bit 608 of thefirst MAC address to 1, so that the second MAC address is the locallyadministered group address version of the first MAC address.

For certain aspects, the second MAC address may be formed by flippingthe least significant address bit, which means that the device has twoglobally administered MAC addresses since the U/L Administered addressbit 608 may not be changed with this method. For other aspects, thesecond MAC address may be formed by setting the least significantaddress bit to 1, with the convention that the first MAC address alwayshas a least significant bit set to 0. As an alternative, the second MACaddress may be formed by setting the least significant address bit to 0,with the convention that the first MAC address always has a leastsignificant bit set to 1.

In addition to the above-mentioned address bits, the second MAC addressmay be formed by flipping a predetermined address bit of the first MACaddress. For other aspects, the second MAC address may be formed bysetting a predetermined address bit of the first MAC address to 1, withthe convention that the predetermined address bit is always 0 in thefirst MAC address. As an alternative, the second MAC address may beformed by setting a predetermined address bit of the first MAC addressto 0, with the convention that the predetermined address bit is always 1in the first MAC address.

For certain aspects, the second MAC address may be signaled in amanagement frame. The second MAC address may be included in themanagement frame as an information element (IE). By sending a managementframe with the second MAC address, the second MAC address need not berelated to the first MAC address.

In operation, a transmitting entity may send a frame to the second MACaddress of the intended receiving entity to indicate that additionalinformation is hidden in the frame, or to indicate that the frame shouldbe parsed or otherwise processed in a different way. The receivingentity may parse or otherwise process a frame received with the secondMAC address differently from a frame received with the first MACaddress, even though both MAC addresses belong to the receiving entity.

The first MAC address may be the address that is provided for addressresolution purposes (i.e., when the address is requested for using theAddress Resolution Protocol (ARP)). For certain aspects, the first MACaddress may be used with data frames, while the second MAC address maybe used with control frames, such as an RTS frame, a CTS frame, or anACK frame. The first MAC address may be used as the Source Address (SA)for any transmission. The second MAC address may be derived from thefirst MAC address through a defined rule (e.g., setting a predeterminedaddress bit of the first MAC address to 1), or the second MAC addressmay be communicated explicitly in a management frame, both as describedabove.

For certain aspects, the information transmitted in a VHT-specificcontrol frame (e.g., an RTS or CTS frame) may include information aboutthe channels on which the control frame was transmitted or on whichchannels a control frame was received. In IEEE 802.11ac networks, thebasic channel unit is 20 MHz wide. Each PPDU (physical layer conversionprotocol (PLCP) protocol data unit) may span 20, 40, 80, or 160 MHz(i.e., one, two, four, or eight 20 MHz channels). For certain aspects,this bandwidth information may be encoded in two or more bits, (e.g.,two or more LSBs) of the Duration field of the MAC header.

Exemplary frame exchanges between a STA A and a STA B usinglegacy-compatible frames are illustrated in FIGS. 8-11. In thesefigures, “A1” represents the first MAC address of STA A, “A2” representsthe second MAC address of STA A, “B1” represents the first MAC addressof STA B, and “B2” represents the second MAC address of STA B.

FIG. 8 illustrates an RTS frame 802 transmitted by STA A to the secondMAC address B2 of STA B as the intended recipient. The RTS frame 802 mayinclude information that is not present in legacy RTS frames, such asVHT-specific information. STA B may parse the received RTS frame 802 ina different manner from typical parsing for legacy RTS frames to extractthis information.

In response to receiving the RTS frame 802, STA B may transmit a CTSframe 804 to the second MAC address of STA A as the intended recipient.The CTS frame 804 may also include information that is not present inlegacy CTS frames, such as VHT-specific information.

Upon receiving the CTS frame 804, STA A may transmit a data frame 806with the first MAC address, indicating that the data frame should beparsed by STA B in the same manner as typical parsing for legacy dataframes. To acknowledge receipt of the data frame 806, STA B may transmitan ACK frame 808, such as a block acknowledgment (BA), to the first MACaddress of STA A as the intended recipient.

FIG. 9 illustrates an RTS frame 802 transmitted by STA A to the secondMAC address B2 of STA B, followed by a CTS frame 902 transmitted by STAB to the first MAC address A1 of STA A. Unlike the CTS frame 804 in FIG.8, the CTS frame 902 in FIG. 9 may only include information that ispresent for legacy CTS frames. This RTS/CTS exchange may be followed bya data/ACK exchange between the first MAC addresses of STA A and STA Bas described above for FIG. 8.

FIG. 10 illustrates an RTS/CTS exchange between the second MAC addressesas described above for FIG. 8. This may be followed by STA Atransmitting a data frame 1002 to the second MAC address of STA B,indicating that the data frame includes information not present inlegacy data frames. In response to receiving the data frame 1002, STA Bmay parse the data frame 1002 to extract the data including the newinformation and may then transmit an ACK frame 1004 to the second MACaddress of STA A, indicating that the ACK frame 1004 includesinformation not present in legacy ACK frames.

FIG. 11 illustrates a data/ACK exchange between the second MAC addressesof STA A and STA B as described above for FIG. 10. In this scenario, anRTS/CTS exchange need not be performed prior to the data/ACK exchange.

In an example transmitter scenario, a data frame may be sent to aspecific Receiver Address (RA). The MAC layer may determine that thetransmission should be preceded by an RTS frame, that the device withthe RA is 802.11ac-capable, and that 802.11ac-specific information willbe included in the RTS frame. The MAC layer may form the802.11ac-specific RTS frame and include the second MAC address of theintended receiver. The second MAC address may be formed by flipping aspecific bit in the intended receiver's first MAC address.

In an example receiver scenario, a STA may receive an RTS frame that isaddressed to the second MAC address of the STA. The STA may then parsethe received RTS as being 802.11ac-specific. For example, the RTS framemay include information about the channels on which the RTS frame wastransmitted.

The various operations of methods described above may be performed byany suitable means capable of performing the corresponding functions.The means may include various hardware and/or software component(s)and/or module(s), including, but not limited to a circuit, anapplication specific integrated circuit (ASIC), or processor. Generally,where there are operations illustrated in figures, those operations mayhave corresponding counterpart means-plus-function components withsimilar numbering. For example, operations 700 illustrated in FIG. 7correspond to means 700A illustrated in FIG. 7A.

For example, the means for transmitting may comprise a transmitter, suchas the transmitter unit 222 of the access point 110 illustrated in FIG.2, the transmitter unit 254 of the user terminal 120 depicted in FIG. 2,or the transmitter 310 of the wireless device 302 shown in FIG. 3. Themeans for receiving may comprise a receiver, such as the receiver unit222 of the access point 110 illustrated in FIG. 2, the receiver unit 254of the user terminal 120 depicted in FIG. 2, or the receiver 312 of thewireless device 302 shown in FIG. 3. The means for processing maycomprise a processing system, which may include one or more processors,such as the RX data processor 270 and/or the controller 280 of the userterminal 120 or the RX data processor 242 and/or the controller 230 ofthe access point 110 illustrated in FIG. 2.

As used herein, the term “determining” encompasses a wide variety ofactions. For example, “determining” may include calculating, computing,processing, deriving, investigating, looking up (e.g., looking up in atable, a database or another data structure), ascertaining and the like.Also, “determining” may include receiving (e.g., receiving information),accessing (e.g., accessing data in a memory) and the like. Also,“determining” may include resolving, selecting, choosing, establishingand the like.

As used herein, a phrase referring to “at least one of a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: a, b, or c” is intended to cover: a, b, c,a-b, a-c, b-c, and a-b-c.

The various illustrative logical blocks, modules and circuits describedin connection with the present disclosure may be implemented orperformed with a general purpose processor, a digital signal processor(DSP), an application specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA) or other programmable logic device (PLD),discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor may be a microprocessor, but in thealternative, the processor may be any commercially available processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with thepresent disclosure may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination of the two. Asoftware module may reside in any form of storage medium that is knownin the art. Some examples of storage media that may be used includerandom access memory (RAM), read only memory (ROM), flash memory, EPROMmemory, EEPROM memory, registers, a hard disk, a removable disk, aCD-ROM and so forth. A software module may comprise a singleinstruction, or many instructions, and may be distributed over severaldifferent code segments, among different programs, and across multiplestorage media. A storage medium may be coupled to a processor such thatthe processor can read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor.

The methods disclosed herein comprise one or more steps or actions forachieving the described method. The method steps and/or actions may beinterchanged with one another without departing from the scope of theclaims. In other words, unless a specific order of steps or actions isspecified, the order and/or use of specific steps and/or actions may bemodified without departing from the scope of the claims.

The functions described may be implemented in hardware, software,firmware, or any combination thereof. If implemented in hardware, anexample hardware configuration may comprise a processing system in awireless node. The processing system may be implemented with a busarchitecture. The bus may include any number of interconnecting busesand bridges depending on the specific application of the processingsystem and the overall design constraints. The bus may link togethervarious circuits including a processor, machine-readable media, and abus interface. The bus interface may be used to connect a networkadapter, among other things, to the processing system via the bus. Thenetwork adapter may be used to implement the signal processing functionsof the PHY layer. In the case of an access terminal 110 (see FIG. 1), auser interface (e.g., keypad, display, mouse, joystick, etc.) may alsobe connected to the bus. The bus may also link various other circuitssuch as timing sources, peripherals, voltage regulators, powermanagement circuits, and the like, which are well known in the art, andtherefore, will not be described any further.

The processor may be responsible for managing the bus and generalprocessing, including the execution of software stored on themachine-readable media. The processor may be implemented with one ormore general-purpose and/or special-purpose processors. Examples includemicroprocessors, microcontrollers, DSP processors, and other circuitrythat can execute software. Software shall be construed broadly to meaninstructions, data, or any combination thereof, whether referred to assoftware, firmware, middleware, microcode, hardware descriptionlanguage, or otherwise. Machine-readable media may include, by way ofexample, RAM (Random Access Memory), flash memory, ROM (Read OnlyMemory), PROM (Programmable Read-Only Memory), EPROM (ErasableProgrammable Read-Only Memory), EEPROM (Electrically ErasableProgrammable Read-Only Memory), registers, magnetic disks, opticaldisks, hard drives, or any other suitable storage medium, or anycombination thereof. The machine-readable media may be embodied in acomputer-program product. The computer-program product may comprisepackaging materials.

In a hardware implementation, the machine-readable media may be part ofthe processing system separate from the processor. However, as thoseskilled in the art will readily appreciate, the machine-readable media,or any portion thereof, may be external to the processing system. By wayof example, the machine-readable media may include a transmission line,a carrier wave modulated by data, and/or a computer product separatefrom the wireless node, all which may be accessed by the processorthrough the bus interface. Alternatively, or in addition, themachine-readable media, or any portion thereof, may be integrated intothe processor, such as the case may be with cache and/or generalregister files.

The processing system may be configured as a general-purpose processingsystem with one or more microprocessors providing the processorfunctionality and external memory providing at least a portion of themachine-readable media, all linked together with other supportingcircuitry through an external bus architecture. Alternatively, theprocessing system may be implemented with an ASIC (Application SpecificIntegrated Circuit) with the processor, the bus interface, the userinterface in the case of an access terminal), supporting circuitry, andat least a portion of the machine-readable media integrated into asingle chip, or with one or more FPGAs (Field Programmable Gate Arrays),PLDs (Programmable Logic Devices), controllers, state machines, gatedlogic, discrete hardware components, or any other suitable circuitry, orany combination of circuits that can perform the various functionalitydescribed throughout this disclosure. Those skilled in the art willrecognize how best to implement the described functionality for theprocessing system depending on the particular application and theoverall design constraints imposed on the overall system.

The machine-readable media may comprise a number of software modules.The software modules include instructions that, when executed by theprocessor, cause the processing system to perform various functions. Thesoftware modules may include a transmission module and a receivingmodule. Each software module may reside in a single storage device or bedistributed across multiple storage devices. By way of example, asoftware module may be loaded into RAM from a hard drive when atriggering event occurs. During execution of the software module, theprocessor may load some of the instructions into cache to increaseaccess speed. One or more cache lines may then be loaded into a generalregister file for execution by the processor. When referring to thefunctionality of a software module below, it will be understood thatsuch functionality is implemented by the processor when executinginstructions from that software module.

If implemented in software, the functions may be stored or transmittedover as one or more instructions or code on a computer-readable medium.Computer-readable media include both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. A storage medium may be anyavailable medium that can be accessed by a computer. By way of example,and not limitation, such computer-readable media can comprise RAM, ROM,EEPROM, CD-ROM or other optical disk storage, magnetic disk storage orother magnetic storage devices, or any other medium that can be used tocarry or store desired program code in the form of instructions or datastructures and that can be accessed by a computer. Also, any connectionis properly termed a computer-readable medium. For example, if thesoftware is transmitted from a website, server, or other remote sourceusing a coaxial cable, fiber optic cable, twisted pair, digitalsubscriber line (DSL), or wireless technologies such as infrared (IR),radio, and microwave, then the coaxial cable, fiber optic cable, twistedpair, DSL, or wireless technologies such as infrared, radio, andmicrowave are included in the definition of medium. Disk and disc, asused herein, include compact disc (CD), laser disc, optical disc,digital versatile disc (DVD), floppy disk, and Blu-ray® disc where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers. Thus, in some aspects computer-readable media maycomprise non-transitory computer-readable media (e.g., tangible media).In addition, for other aspects computer-readable media may comprisetransitory computer-readable media (e.g., a signal). Combinations of theabove should also be included within the scope of computer-readablemedia.

Thus, certain aspects may comprise a computer program product forperforming the operations presented herein. For example, such a computerprogram product may comprise a computer-readable medium havinginstructions stored (and/or encoded) thereon, the instructions beingexecutable by one or more processors to perform the operations describedherein. For certain aspects, the computer program product may includepackaging material.

Further, it should be appreciated that modules and/or other appropriatemeans for performing the methods and techniques described herein can bedownloaded and/or otherwise obtained by a user terminal and/or basestation as applicable. For example, such a device can be coupled to aserver to facilitate the transfer of means for performing the methodsdescribed herein. Alternatively, various methods described herein can beprovided via storage means (e.g., RAM, ROM, a physical storage mediumsuch as a compact disc (CD) or floppy disk, etc.), such that a userterminal and/or base station can obtain the various methods uponcoupling or providing the storage means to the device. Moreover, anyother suitable technique for providing the methods and techniquesdescribed herein to a device can be utilized.

It is to be understood that the claims are not limited to the preciseconfiguration and components illustrated above. Various modifications,changes and variations may be made in the arrangement, operation anddetails of the methods and apparatus described above without departingfrom the scope of the claims.

1. (canceled)
 2. An apparatus for wireless communications, comprising: aprocessing system configured to select a first Media Access Control(MAC) address from at least two MAC addresses associated with a device,wherein the selected first MAC address indicates of how the device is toparse a first frame; and a transmitter configured to transmit the firstframe containing the first MAC address to the device.
 3. The apparatusof claim 2, wherein the processing system is configured to indicate, viaselection of the first MAC address, whether the device is to parse thefirst frame by interpreting the first frame as a legacy frame or as avery high throughput (VHT) frame.
 4. The apparatus of claim 2, whereinthe processing system is configured to provide, in the first frame,information about one or more channels on which the first frame istransmitted.
 5. The apparatus of claim 4, wherein the information isindicated by two or more least significant bits (LSBs) of a field of thefirst frame.
 6. The apparatus of claim 2, wherein: the processing systemis further configured to select a second MAC address from the at leasttwo MAC addresses associated with the device, wherein the selectedsecond MAC address is different than the first MAC address and indicateshow the device is to parse a second frame differently than the firstframe; and the transmitter is further configured to transmit the secondframe.
 7. The apparatus of claim 5, wherein the first frame comprises acontrol frame.
 8. The apparatus of claim 6, further comprising areceiver, wherein the control frame comprises a Request to Send (RTS)frame, wherein the receiver is configured to receive, from the device, aClear to Send (CTS) frame in response to the RTS frame, and wherein thesecond frame comprises a data frame transmitted in response to the CTSframe.
 9. The apparatus of claim 5, wherein the first MAC addressdiffers from the second MAC address by only one address bit.
 10. Theapparatus of claim 8, wherein the one address bit comprises anIndividual/Group (I/G) address bit, a Universally/Locally (U/L)Administered address bit, or a least significant address bit.
 11. Theapparatus of claim 2, wherein the processing system is configured togenerate a management frame notifying the device that frames comprisingthe indication of the first MAC address are intended for the device. 12.A method for wireless communications by an apparatus, comprising:selecting a first Media Access Control (MAC) address from at least twoMAC addresses associated with a device, wherein the selected first MACaddress indicates of how the device is to parse a first frame; andtransmitting the first frame containing the first MAC address to thedevice.
 13. The method of claim 12, wherein the selected first MACaddress indicates whether the device is to parse the first frame byinterpreting the first frame as a legacy frame or as a very highthroughput (VHT) frame.
 14. The method of claim 12, further comprisingproviding, in the first frame, information about one or more channels onwhich the first frame is transmitted.
 15. The method of claim 14,wherein the information is indicated by two or more least significantbits (LSBs) of a field of the first frame.
 16. The method of claim 12,further comprising: selecting a second MAC address from the at least twoMAC addresses associated with the device, wherein the selected secondMAC address is different than the first MAC address and indicates howthe device is to parse a second frame differently than the first frame;and transmitting the second frame.
 17. The method of claim 16, whereinthe first frame comprises a control frame.
 18. The method of claim 17,wherein: the control frame comprises a Request to Send (RTS) frame; themethod further comprises receiving, from the device, a Clear to Send(CTS) frame in response to the RTS frame; and the second frame comprisesa data frame transmitted in response to the CTS frame.
 19. The method ofclaim 16, wherein the first MAC address differs from the second MACaddress by only one address bit.
 20. The method of claim 19, wherein theone address bit comprises an Individual/Group (I/G) address bit, aUniversally/Locally (U/L) Administered address bit, or a leastsignificant address bit.
 21. The method of claim 12, further comprisinggenerating a management frame notifying the device that framescomprising the indication of the first MAC address are intended for thedevice.
 22. An apparatus for wireless communications, comprising: meansfor selecting a first Media Access Control (MAC) address from at leasttwo MAC addresses associated with a device, wherein the selected firstMAC address indicates of how the device is to parse a first frame; andmeans for transmitting the first frame containing the first MAC addressto the device.
 23. A computer readable medium storing computerexecutable code for: selecting a first Media Access Control (MAC)address from at least two MAC addresses associated with a device,wherein the selected first MAC address indicates of how the device is toparse a first frame; and transmitting the first frame containing thefirst MAC address to the device.
 24. An access point, comprising: atleast one antenna; a processing system configured to select a firstMedia Access Control (MAC) address from at least two MAC addressesassociated with a device, wherein the selected first MAC addressindicates of how the device is to parse a first frame; and a transmitterconfigured to transmit, via the at least one antenna, the first framecontaining the first MAC address to the device.